The present disclosure relates to a controller and a control method for an internal combustion engine that is provided with a plurality of detected units provided in a rotation member, which rotates integrally with a crankshaft, at a plurality of preliminarily set crank angle, and a specific crank angle sensor which is fixed to a nonrotation member and detects the detected unit.
The technology described in JP 6012892B is already known, concerning the above controller. In the technology of JP 6012892 B, the crank angle speed, the crank angle acceleration, and the crank angle jerk are calculated based on the output signal of the crank angle sensor; the error of the crank angle interval is corrected based on the crank angle jerk; and the cylinder internal pressure is estimated based on the crank angle speed and the crank angle acceleration after correction. Although it is described in the paragraph 0119 of JP 6012892 B that misfire detection may be performed using this technology, any concrete method of misfire detection is not described.
About misfire detection, for example, the technology described in JP 3495463 B is already known. JP 3495463 B describes a method for calculating TL(i) which shows a period from B76 to B06, TU(i) which shows a period from B06 to B76, TA(i) which shows a period from B76 to B76, and TS(i) which shows a period from B06 to B06, based on a BTDC 76 degrees signal (hereinafter, B76) and a BTDC 6 degrees signal (hereinafter, B06), and further calculating an angular acceleration α and a period ratio S based on these to perform misfire detection.